1. Field of the Invention
The invention relates to a DLC-coated member having a base that is coated, at least partially, with a DLC film.
2. Description of Related Art
In order to increase fuel economy of motor vehicles, reduction of the slide resistances of various slide parts mounted in motor vehicles is required. Therefore, in some cases, the surface of a base, which is a base member of a slide part, is coated, at least partially, with a DLC (Diamond Like Carbon) film that has low friction and high wear resistance (high hardness) (refer to Japanese Patent Application Publication No. 2000-71103). In general, the adhesion of a DLC film to a base is low. Therefore, there are demands for increasing the adhesion of a DLC film to a base.
For the purpose of increasing the adhesion of a DLC film, forming an intermediate layer constituted of a single layer film made of, for example, SiC between a base and a DLC film has been proposed, as described in Japanese Patent Application Publication No. 2000-71103.
However, even if an intermediate layer constituted of a single layer film, such as the one described in Japanese Patent Application Publication No. 2000-71103, is formed between a base and a DLC film, a sufficiently high adhesion of the DLC film to the base is not achieved. Meanwhile, another possible option for increasing the adhesion of a DLC film is to form a nitrided layer or a carburized layer on the surface of a base by performing a nitriding treatment (e.g., plasma nitridation) or a carburizing treatment (e.g., plasma carburization) before forming the DLC film.
However, in order to form a nitrided layer or a carburized layer that provides a sufficiently high adhesion, it is necessary to perform a nitriding treatment or a carburizing treatment in a high temperature environment. This narrows the range of choice for the material of a base. Therefore, in order to increase the adhesion of a DLC film to a base while securing a sufficiently wide range of choice for the material of the base, it is necessary to form an appropriate intermediate layer between the base and the DLC film.